The Irish standard., 1887-02-05
PLANE DISPERSION.
The Part Taken by Birds in This
Important Work.
Two Ways In Which Seeds Are Carried by
INHERENT Species of Birds--The Agency
to Which the World Is Indebted
for Its Pepper Supply.
ID. Morris, in Nature.1

for Its Pepper Supply.
ID. Morris, in Nature.1
The part taken by birds in the dispersion
Of plants is one Of great interest in view Of
the difficulty of accounting for the appear
ance::of certain species inremote islands, no
less than in localities nearer to each other,
or divided by such barriers as mountain
ranges Or deep seas. This subject has,
more or less, engaged the attention of
botany travellers from the time when Dar
win published his classical " journal Of
Researches nearly fifty years ago, down
to the publication OF Mr. Hemsley's "Bota-
ny of the Challenger Expedition" In the
careful summary Of plants probably dis
tributed by birds, it is mentioned that
seeds may be carried by birds in either
Of two ways: First, by seeds, especially
those provided with barbs and hooks, at
taching themselves to the feathers Of
birds, and in the case of aquatic or;
Durrowing birds being embedded I'M
mud and thus carried accidentally outside;
Or, secondly. by seeds swallowed by fru-
givorous birds being for a time lodged
within, and detected afterwards in such a
state as to be capable Of termination. My;
object now is rot to treat generally OF this
subject, but to place on record two re-
lnarl1able and striking instances where
seeds carried and dispersed by birds have
come Immediately under my own observa'
ton, The examples which shall here de-
scribe will, I believe, show clearly that
birds are capable of acting as very effective
agents in the dispersal Of plants, and that
the results are so apparent as to be placed
beyond reasonable doubt. In cases where
seeds of light character are provided with
barbs and hooks, they are we'll adapted for
attaching themselves to passing objects.
and are most favocably placed for disper.
sal by means Of birds. The particular
plant with barhe1 seeds which described
under this category has not, belive, been
mentioned before; but it is deserving OF
notice, as it fully meets all the require
1ne1its incidental to this form of dispe rsal,
and, moreover, have had, for some years,
very favorable opportunities Of observing
its behavior. This plant is U1cnia ja,nujce,eSis,
Pers. (Capeyacee), which grows in damp
places in the mountains Of Jamaica, at ele.
vations Of 5000 to 5000 feet. 1t is general
ly found overhanging small pools Of stag
nant water or on banks of mountain rivu-
let's. It's slender tapering spikes, when
ripe, literally bristle with long exserted
rachilla, each shaped something like a
shepherds crook (h;s,nate>, but with the
hooked part so closely hrJlng and elastic
that, if drawn along the back Of the hand,
it would grasp and draw out the finest
hairs.
Now, such places as are affected by this
Uncinia are also the frequent resort Of
numerous birds that come there to drink
or bathe, or to seek coolness and shaSie.
In the case OF migratory birds, and es-
~.
their flight, the high lands are generally
those first touched. This is doubtless ow-
ing to the elevation at which they fly to
escape surface currents or local objects. J.
have often noticed birds from the north
Che United States) on their way sontll7
and again birds Of the south returning to
the north in early spring, frequenting the
high lands of jamaica and resting there for
a time before continuing their journey.
Some such birds have been easily caught
by hand, SO exhausted were they with their
long fight. In two instances [ have found
small migratory birds so completely Gu
tangled IN the hooks of the Tncinia that
they were unable to extricate themselves:
and, unless set at liberty at the time, would
probably have died in that situation. In
these instances the hooks OF the Unciuia!
ovorsteppod their proper function; for.
obviously, no benefit would arise to the
plant from the death of the birds, but only,
in the removal of the seed to another place.
Larger birds, of course, would not be
caught; but on the other hand. il they
came within reach of the Uncini;,, they
could hardly get away without detaching
a large number Of the fruits and transport.
ing them wherever they went IT follows,
as a matter of course, the UaciMa ,japnai-
ce,.sis is found plentifuNy distributed in the
track Of migratory birds, and is found in
similar situations in the mountains on The
mainland in Central America, Venezuela,
Ecuador, etc. So much for seeds with
barbs and hooks.
We now come to the second class OF
seeds, namely, those which are swallowed
by frugivorous birds and detected in S ate
suitable for termination. The most strilS-
ing examples know Of the dispersion of
such seeds, and Of the results which imme-
diutely follow, are shown in connection
with the pimento industry Of Jamaica,
which depends entirely for its existence on
the offices of frugivorous birds. The pi-
mentc CT commerce is the dried fruit of the
p;nento allspice. or Jamaica pepper tree
(I'imesto vulgars) No other country sup
Plies this article (although the tree itself
is widely distributed both in the West In
dies and on the mainland), and the value of
the exports Of pimento from Jamaica has
reached lin 1ss0) total of 100000 This
is probably the largest spice industry in
the world, and, to repeat what is mentioned
above, it is wholly dependent upon the
action Of frugivorous birds. In Lunan's
''Hortus Jamaicensis,'' published about the
end of last century, it is stated that ''the
usual method in forming a new pimento
plantation, or 'pimento walk is nothing
more than to appropriate piece of wood
land i'll the neighborhood of a planta-
tion already existing; or in a coun-
try where the scattered trees
arc found in native state, the
woods of which being fallen, the trees are
suffered to remain on the ground till they
become rotten and perish. In the course
OF twelve months after the first seasons
(rains), abundance Of young pimento
plants will be found growing vigorously
in all parts OF the land, being, without
doubt, produced from ripe berries scat
tered there by the birds, while the fallen
trees, etc, afford them both shelter and
shade.". In foot-note it is added that
" birds eagerly devour; the ripe seeds of
the pimento, and 1nuting them, propa-
gate these trees in all parts of the woods.